Bargaining is as important for the buyer as it is for the seller!  

As a buyer, you should know that the reason the things at a yard sale are there is because the owner doesn’t want them or need them anymore.  If you know a price is too high, tell them!  The worst they could do is tell you to get lost.   You could get a smaller offer right away.   Regardless, let them know that you know what you are talking about and that may help with other items in the sale.  

As a seller, remember, you don’t need the junk you are trying to get rid of.   Get rid of it at a reasonable price!  Don’t use eBay to price your items unless you are willing to accept 30-50 percent off of any eBay price.  You must realize that a lot of the shoppers coming to you are doing so to sell items like yours on-line for a profit.   However, as a seller, you should know prices.  Ebay may have a price, but to a collector, some items may be worth more especially since they don’ t have to incur shipping charges.  Regardless, you are in control of prices and you have to consider, do you really want to put these items away again until next year??